The described aspects relate generally to wireless communication systems. More particularly, the described aspects relate to techniques for outer loop management in a multiple output (MO) system.
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSDPA), which provides higher data transfer speeds and capacity to associated UMTS networks.
For MO systems that include a single stream and other multiple streams, a same processing scheme to process the single stream and the multiple streams may be inefficient. For example, due to the varying granularity between the channel quality indicator (CQI) for the single stream and the multiple streams, changes in channel conditions may not be readily reflected in the CQI Improvements in MO systems that include a single stream and other multiple streams are required.